Originally Posted by Sdscustomz
Thanks for the info. Im pretty sure that an 8.3 coach will get the job done. and there is always a fuel plate and injectors that could put it north of 400, my only hesitation is that most of the md3060's are only rated at 300 as per the allison tech that shot me a printout.
Thus shifting my attention towards a m-11 machine. the 4000 series will take about anything that the m-11 could throw at it, even if I had it reflashed to 500hp. Not sure that it would be needed though. It would just be an option! I also like the real Jake that the m-11 is outfitted with, some true downhill whoa power. I had a Pete with a retarder, and while descent I was never impressed with a retarder after having another truck with a Jake. I havent ever had a rig with a Jake and an auto though
The transmission really doesn't care about HP, it is torque that will determine the size of transmission required. The MD3060 has a limit of 1250 ft./lbs. of torque as what it can handle. They are installing the MD3060 behind all ISL engines rated at anywhere from 370 hp (early versions) to 450 hp (later versions).
The only recommendation I would give when upgrading the 8.3c with a fuel plate for more power is to install a pyrometer and keep and eye on those exhaust temperatures as well as engine temps. If you really want to push it you may end up having to setup your radiator with a misting system or something similar to handle the extra heat. Radiator size is what will expel heat from the engine and the biggest issue you will have when upping the power levels it getting rid of the heat.
As far as "reflashing" the M-11 to get to 500 hp, that is not an option on that engine as it is a mechanically injected engine. The newer high pressure common rail engines, such as the ISC, ISL, ISM and ISX, are all computer controlled engines and can have some power added by software changes although there are limits there as well.
Adding fuel to a diesel engine makes power, however, there are limits as too much fuel and all you are doing is throwing money out the tailpipe (black smoke). The proper way to increase HP/torque is to add fuel mixed with the proper amount of air. This usually requires things like larger turbos, larger and better CAC's in addition to some software changes. This is simply not practical on most coaches due to fitment issues with things like radiators, CAC's, transmission coolers and everything else they cram in tight quarters.
If you are requiring large HP and Torque you are much better off purchasing the coach with the appropriate engine that you are trying to squeeze more power out of an engine that you don't think you will be happy with from the get go.
That said, most any coach/engine/transmission combo out there will tow/haul a pretty large load. It is merely what you can live with as far as performance on grades.
We started with a little 300HP CAT 3208 in out last coach and towed an 8500 pound trailer around most of the western U.S. for 7 years and 65k miles. It performed well for its engine size and the weight. Did we get passed on grades by other coaches? Hell yes. Did we get up the grades? Hell yes. Did we still enjoy the coach and create family memories along the way? Hell yes.